CHRONOPHOTOGRAPHY ON MOVING PLATES 119 



as much of it as has been used in taking the photo- 

 graphs. That this may work properly, the end of the 

 strip of paper which is last wound round the supply 

 bobbin must be fixed in the slit of the receiving 

 bobbin. The method of rolling is represented in 

 Fig. 84. The two bobbins being placed on their 

 respective pins, the strip of paper passes through a 

 vertical slit, and through which it keeps running, 

 pulling the sensitized film after it. Two pressure 

 rollers (r r, Fig. 80) are applied to the surface of the 

 bobbins to ensure regularity in rolling and unrolling. 



Fig. 84. — Supply bobbin ready charged. M, the end of the paper which covers it, 

 must be unrolled and wound round the receiving bobbin, R, in an opposite 

 direction. 



We shall not describe the mechanism which produces 

 the intermittent movement of the film. The new 

 arrangement which we have adapted to the apparatus 

 for making the operation more certain, and its employ- 

 ment more easy, differs noticeably from that which we 

 have described before.* 



It would be better for the beginner, instead of 

 relying on a written description, to make a few 

 experiments with a strip of ordinary paper in place 

 of the sensitized film, and thus he would soon acquire 

 proficiency in filling the bobbins, and passing them 

 quickly into their proper chamber. 



* Revue Ge'nerale des Sciences, November 15, 1891. 



